This document discusses techniques for quantifying aortic stenosis and aortic regurgitation using transesophageal echocardiography. It describes using the simplified Bernoulli equation and continuity equation to calculate pressure gradients and regurgitant volumes. Measurement of velocities, pressure half-times, and jet widths are described for assessing severity of aortic regurgitation, while mean and peak gradients help indicate severity of aortic stenosis. Factors like cardiac output and the presence of other valve diseases are also accounted for in the quantification.

1. TEE Quantification of Aortic Stenosis and Aortic RegurgitationDr PK Neema

2. Normal Aortic valveME Sax view transducer at 40o

3. Normal flow-dynamicsAortic velocity Vmax 1-1.2m/secLVOT max velocity 0.9-1.1 m/secP2V1 = V2P1 = P2V2V1P1

4. AS and its effect on Flow-dynamicP1 > P2V2 > V1

5. Doppler principle

6. Effect of interrogation angle on frequency shift

7. Ultrasound beam should be parallel to the flow under studyThe ultrasound should intercept the center of the flow not the peripheryThe interrogation angle should be < 15oThe view optimal for the imaging may not be the optimal view for the Doppler study Essentials during Doppler study

8. Transgastric Lax view (Transducer at 130o)TEE Views for Doppler study

9. Deep Transgastric Lax viewTEE Views for Doppler study

10. Simplified Bernoulli equationContinuity equationMethods to quantify AS

11. Simplified Bernoulli equationP = 4V2 2P – Pressure gradientSevere AS = P > 75 mmHg

12. Deep Transgastric Lx View

13. Peak velocityMean velocityPeak gradient 4V2Mean gradientVelocity time integral (VTI) or TVIMeasurements

14. Continuity equation

15. Continuity equationBlood flow through LVOT = Blood flow through AoVBlood flow through LVOT = CSA LVOT X TVI LVOTBlood flow through AoV = CSA AoV X TVI AoVCSA LVOT X TVI LVOT = CSA AoV X TVI AoVCSA AoV = LVOT flow/TVI AoV

16. The LVOT diameter is measured in ME Lax view at 130o and measured from endocardium to endocardium at the level of insertion of AV leaflets in midsystoleInaccuracy in the measurement of diameter can result in gross error since the radius of the LVOT is squared for calculating area (CSA = πr2)Assessment of LVOT areaME Lax View Xducer at 130o

17. The TVI is measured by Doppler interrogation through LVOT using pulse wave Doppler (PWD) The sample volume is assessed just proximal to the aortic valve within the LVOT where the annular dimension is measuredTVI Measurement in LVOT Transgastric Lax view

18. Severity of AS

19. AS and Mitral regurgitationLow cardiac output Aortic regurgitationFallacies

20. The MR jet can be mistaken for that of AS. How to avoid the MR jet? The MR jet should be visualized during colour Doppler imaging and the MR jet path should be consciously avoided. How to confirm?The MR jet starts early with LV contraction, the AS jet starts later in systole. The MR jet starts in the early portion of QRS complex while AS jet starts in the mid or late portion of QRS complex. Determination is facilitated by recording the jets at a faster sweep speed (100 mm/s)AS and Mitral regurgitation (MR)

21. Gorlin formula (AVA = Cardiac output/ 44.3 (SEP) (HR) √mean gradientThe CO is an important determinant of valve area and a decrease in CO result in a decrease in the peak aortic gradient and the severity of AS Accordingly, one should assess LV function before ‘small gradients’ are reported as insignificant. Dobutamine stress test and dimensionless index are evaluated to assess AS severity in presence of low CO.AS and Low cardiac output

22. High CO, similar to low CO, result in over estimation of peak gradient and AS severity.The discrepancy is corrected by measuring the blood flow velocity in the LVOT and applying a correction if the measured LVOT peak velocity exceeds 1.5 m/s. Peak gradient in presence of significant aortic regurgitation = 4 [(peak velocity)2 – (LVOT velocity)2]AS and Aortic regurgitation

23. Dobutamine (5-10 μg/kg/min) is infused to increase COAn increase in pressure gradient suggests severe valvular disease. No or borderline increase in pressure gradient suggest primary myocardial disease as the cause of low gradient and contraindicate valve replacement as the primary therapy; However, AS is a unique cardiovascular disease where patients with a low EF may normalize after valve replacement.Dobutamine stress test

24. LVOT and aortic TVI ratio or peak LVOT and aortic velocity ratio of 0.25 or less indicates critical AS. Useful in evaluation of patients with prosthetic aortic valves where measurement of aortic annular dimensions is not clear.Dimensionless index

25. Aortic RegurgitationME Lax view Transducer at 130o

26. Based onColor flow Doppler (Jet width and jet area measurement)Continuity equationRegurgitant jet velocity assessmentAR quantification

27. TEE view for jet width measurementME Lax view Transducer at 130o

28. Jet width to LVOT diameter ratio Jet width-LVOT diameter ratio > 65% indicate severe AR

29. Color M mode75/214=0.35

30. LVOT ShadowingAortic prosthesisMitral prosthesisSite and shape of the orifice (Eccentric jet, multiple jet)Jet width limitations

31. TEE views for jet area measurementME Sax view Transducer at 40o

32. 1+ < 4% (trivial)2+ 4-24 (mild) 3+ 25-59 (moderate) 4+ >60 (severe)Jet area/LVOT area

33. Vena ContractaVena Contracta width of > 6 mm indicate Severe AR

34. Blood flow through LVOT = CSA LVOT X TVI LVOT Blood flow through RVOT = CSA RVOT X TVI RVOTRegurgitant volume = CSA LVOT X TVI LVOT – CSA RVOT X TVI RVOT EROA = Regurgitant volume/VTI (VTI measured by PWD) Continuity equation

35. Deceleration Slope and Pressure-half timeThe velocity of regurgitant jet during diastole is directly related to pressure gradient between aortic root and LV.A large regurgitant defect will rapidly decrease pressures gradient and the velocity of regurgitant jet, hence slope of AR jet indicate severity of ARCWD analysis of AR jet transgastric or deep transgastric view

36. Regurgitant jet Slope DecayMild ARSevere AR (>3m/sec2)CWD LVOTAoAoLV pressureLV

37. LVEDP – Ischemia, LV dysfunctionLow Aortic diastolic pressureEccentric jetsAcute AR vs. C/c ARCWD-Deceleration slope limitations

38. Holo-diastolic flow reversalSevere AR

39. Severity of Regurgitation3-6 mm<3 mm